/// 提升任务优先级别，并且返回之前的优先级。
pub type EfiRaiseTpl = extern "efiapi" fn(new_tpl: EfiTpl) -> EfiTpl;
/// 将任务的优先级恢复到原先的值
///
/// + old_tpl: 用来恢复的原有的优先级别，需要和 raise_tpl 的调用匹配。
pub type EfiRestoreTpl = extern "efiapi" fn(old_tpl: EfiTpl);
pub type EfiTpl = usize;

pub const TPL_APPLICATION: EfiTpl = 4;
pub const TPL_CALLBACK: EfiTpl = 8;
pub const TPL_NOTIFY: EfiTpl = 16;
pub const TPL_HIGH_LEVEL: EfiTpl = 31;
